The official 2023 Newsletter is out! Read here!
Can you do it with SAI or Paint?
I'd have to say that the tutorial is fairly nice and easy to interpret, but you don't really need GIMP. Any program that allows for transparency will do (Paint.NET and Photoshop are two of the more common ones). You can also just open a new image that's 512x512, erase the white space, and name it preset_(number)equip.png. Just wanted to point these things out if you weren't aware. ^^'